Linux, Oracle, Hadoop.

Monthly Archives: April 2010

Here’s a little trick question. Check out the execution plan below. What the hell, shouldn’t the INDEX/TABLE access be the other way around?! Also, how come it’s TABLE ACCESS FULL (and not by INDEX ROWID) in there? This question is … Continue reading →

Did you know that it’s possible to use EXPLAIN PLAN FOR CREATE INDEX ON table(col1,col2,col3) syntax for explaining what exactly would be done when an index is created? That’s useful for example for seeing the Oracle’s estimated index size without … Continue reading →

I recently consulted one big telecom and helped to solve their sporadic performance problem which had troubled them for some months. It was an interesting case as it happened in the Oracle / OS touchpoint and it was a product … Continue reading →

Some time ago I wrote that since Oracle 10.2, some of the buffer cache can physically reside within shared pool granules. I just noticed this in an 11.2 instance: SQL> select * from v$sgastat where name like ‘KGH%'; POOL … Continue reading →

Gwen Shapira has written an article about a good example of a non-trivial performance problem. I’m not talking about anything advanced here (such as bugs or problems arising at OS/Oracle touchpoint) but that sometimes the root cause of a problem … Continue reading →